Screen Printed Electrochemical Sensor for Ascorbic Acid Detection Based on Nafion/Ionic Liquids/Graphene Composite on Carbon Electrodes

The material modification of thick film sensor electrodes is being developed to enhance the performance of sensing capabilities such as stability, sensitivity, and limit detection. The utilization of graphene, ionic liquid, and Nafion has become a key factor to obtain a good material as modifiers in electrochemical sensors. This disposable modified electrode exhibits excellent current enhancement, fast electron transfer kinetics, and chemical stability properties. In this research, a screen-printed electrochemical sensor was fabricated by modifying the carbon working electrode with a combination of Nafion, ionic liquid, and graphene to determine ascorbic acid. The prototype ascorbic acid (AA) sensors show peak oxidation at a potential 0.3 V vs reference Ag|AgCl. Analytical characteristics of the prototype sensors were investigated with a linear calibration curves of AA concentrations over the range from 0.25 to 2 mM (R2 ~ 0.9912). The sensor has sensitivity around 15.95 nA M−1 cm−2 and the limit of detection was 164 μM. The cyclic voltammogram result indicate that the modified working electrode can increase the redox peak current higher than the bare working electrode. Thus, the modified electrode of thick film sensors could provide a promising platform for the sensor of ascorbic acid detection.